British Airways boss Willie Walsh has labelled the government's air passenger duty tax (APD) a "disgrace" and said it will have a big impact on the economies of developing countries as well as Britain.

Walsh said APD, which raises £2.3bn a year for the Treasury, is expected to generate £3.8bn by 2015 – a rise of 65%. Warning that rising passenger numbers could not accommodate that increase, he said the tax levy on individual fliers would have to rise in order to meet targets. "This tax is a disgrace," he said.

Speaking in Barbados, Walsh said the impact would be felt in developing regions such as the Caribbean. Citing a 12% drop in arrivals in the Caribbean from the UK since the APD charge for a family of four went from £120 to £200 last November, he said the tax threatened economic development. "This obsession with taxes on flying … will inflict considerable harm on airlines and their ability to do good for society."

Walsh spoke as BA's biggest cabin crew union, Bassa, indicated that a new peace deal could be brokered with the firm in a long-running industrial dispute. Tony Woodley, joint general secretary of Bassa's parent union, Unite, held talks with Walsh last week. In an email to members Bassa said the announcement of a fresh strike poll had been delayed to allow talks to continue. "We have been informed Tony believes that he should be able to conclude a new proposal, with significant changes, by the middle of next week at the latest."